Dead gm 90

[mobile chicane]

Hi all I think I've kipperd my gm 90 speedo, I broke the sensor socket and a friend at my local club has replaced it for me but even though the speedo still programs and runs its very down on power and stutters badly when at full throttle.

I've subtituted a difrent gm 90 spedo in its place so I know the motor, battery sensor lead etc are ok.

is there anywhere in the uk that can repair these or is it a send to germany job ?